The present invention relates to a diversity receiving apparatus for receiving a signal by space diversity and, more particularly, to a vehicle-mounted space diversity receiving apparatus.
A diversity receiving apparatus for receiving signals transmitted by radio waves by space diversity is known in the art. This kind of receiving apparatus has a plurality of antennas for picking up radio signals. The signals picked up by the individual antennas are switched over or combined and then fed to a diversity receiver. A prerequisite with such an apparatus is that the antennas be spaced apart from each other. When the diversity receiving apparatus is mounted on a vehicle, the individual antennas are affixed to the roof, windshields and so forth of the vehicle. Each antenna is connected to the diversity receiver by an exclusive antenna feeder which propagates a signal therethrough.
When one of antenna circuits or channels included in the diversity receiving apparatus and constituted by an antenna, antenna feeder and so forth fails, the apparatus is capable of receiving a signal by the other antenna circuits. In this condition, despite that the receiving ability of the apparatus has been degraded, the reception seemingly remains normal. The user, therefore, often overlooks such a failure of the antenna circuit. This problem is especially serious when it comes to a vehicle-mounted diversity receiving apparatus, because antenna feeders of the apparatus are apt to break due to vibrations and impacts particular to on-road vehicles.